Tubular lamp tipping-off apparatus



Nov. 25, 1952 R. A. KUEBLER 2,618,903

TUBULAR LAMP TIPPING-OFF APPARATUS Filed July 12, 1950 3 Sheets-Sheet 1Fij 1. '1

{I q k; /2 4 3 Invewiror: lQober k A Kuebler', 9 MM C" His A=t=lrorneNov. 25, 1952 R. A. KUEBLER 2,618,903

TUBULAR LAMP TIFPING-OFF APPARATUS Filed July 12, 1950 5 Sheets-Sheet 2lmentrorz I Robefitr A. KuelpLer,

His A't'tomey.

Nov. 25, 1952 R. A. KUEBLER 2,618,903

TUBULAR LAMP TIPFING-OFF APPARATUS Filed July 12, 1950 Y s Sheets-Sheeta Patented Nov. 25, 1 95.?

TUBULAR LAMP TIPPING-OFE APPARATUS Robert A. Kuebler, UniversityHeights, Ohio, assignor to General Electric Company, a corporation ofNew York Application July 12, 1950, Serial No. 173,447

9 Claims.

This invention relates generally to the sealing of vitreous vessels andmore particularly to the tipping-01f of the exhaust tubes of elongatedgaseous discharge devices such as fluorescent l-amps.

The present application is a continuation-inpart of my copendinapplication Serial No. 669,140, filed May 11, 1946, and since abandonedin view of the filing of this application. It presents certainimprovements in the tipping-off device described in the afore-mentionedapplication, particularly with regard to automatic recentering of thedevice, which improvements were necessitated by the coming into generaluse of longer fluorescent lamps than were being manufactured at the timethat application was filed.

In the manufacture of electric lamps, it is necessary to provide forexhausting and sealing oif the glass envelope. The actual sealing oficomprises heating an exhaust tube extending from an end of an electriclamp to its melting point so that it is fused into a tip which seals thelamp permanently. This operation is generally known as tipping-off thelamp. The purpose of the exhaust tube, it will be understood, is topermit exhausting air from the interior of the bulb or envelope and alsoto permit filling with gas and, in certain instances, to permit theintroduction of other substances such as mercury.

In the case of elongated tubular discharge devices, such as the commonfluorescent lamp, exhaust tubes are generally provided at both ends ofthe device. This simplifies processing and permits flushing the envelopeby injecting gas into one end and expelling it through the exhaust tubeat the other end. Also, the exhaust tubes may afiord means for holdingone of the elements of the lamp, such as the stem, during its course ofmanufacture, in particular for mounting the filaments on the lead-inwires.

The tipping-01f or sealing operation is usually accomplished by the heatand pressure of a gas flame directed against a portion of the vitreousexhaust tube and occurs while the electrical device from which theexhaust tube extends is retained by other associated apparatus, such asan exhausting and gas filling machine. These machines may be of theturret type comprising a series of heads for holding the lamps whilevarious operations are performed upon them. The turret indexes each headto various work stations at spaced time intervals during which thespecific manufacturing operations take place. The tipping-off apparatusmay be located adjacent one of these work stations and must move intooperative engagement with the lamp while it is still retained in theparticular head to which it was attached when first placed in the turretmachine. In order to realize the full benefits of its combination withthe turret machine, the tipping-off apparatus must be operatedautomatically and in proper synchronism with the indexing system.

The principal object of my invention is to provide automatic tipping-offapparatus for operation in combination with automatic lamp makingmachinery which periodically carries an electrical device provided witha vitreous exhaust tube to a work station occupied by the apparatus.

Another object of my invention is to provide tipping-off apparatus ofthe afore-mentioned character which is adapted to move automatically tothe correct operating position relative to electrical devicessuccessively located at a work station by means of associated apparatus.

Still another object of my invention is to provide self-positionin andautomatic recentering tipping-off apparatus adapted to assume thecorrect operating position relative to successive electrical devicespresented at a work station, the positions of these devices being onlyapproximately determined or fixed by means of associated apparatus.

It will be understood that tipping-01f apparatus is available for takinga definite operating position relative to a work station and that noproblem is presented thereby. However, where the position of thatportion of the lamp adjacent the exhaust tube which is to be tipped-offis subject to considerable variation, an entirely difierent problem isencountered which requires a different solution. Variations in positionof the type in question here may occur because the devices, such as longtubular fluorescent lamps, are supported at points remote from the endwhich the tipping-off apparatus is required to engage. The fluorescentlamps may not be perfectly straight or, again, bowing may occur as aresult of unequal cooling of difierent sides of the lamp. It willreadily be understood that in the case of an eight-foot lamp, such as a96-T-12, a very slight variation in the temperature of one side of thelamp with respect to the other may cause a bow- I ing and lateraldisplacement at one end of as much as one inch when the lamp issupported exclusively from the other end. The tipping-off apparatus inaccordance with my invention is designed to take care of variations inpositioning of this order.

For further objects and advantages and for a better understanding of myinvention, attention is now directed to the following description andaccompanying drawing. The features of my invention believed to be novelwill be more particularly pointed out in the appended claims.

In the drawings:

Fig. 1 is a pictorial representation, considerably simplified in certainrespects, illustrating the application of the tipping-011 apparatus ofmy invention to a turret type sealing and exhausting machine for longfluorescent lamps.

Fig. 2 is a side elevation of a tipping-off device embodying myinvention and shown in operating relationship to a fluorescent lampretained by the head of an associated exhausting apparatus. Certainsections of the device have been broken away in order to illustrate moreclearly the construction of the internal parts.

Fig. 3 is a plan View of the tipping-off device of Fig. 1.

Fig. 4 is a side elevation, likewise with certain sections broken away,of another tipping-off device embodying an improved form of my inventionwhich is particularly suitable for very long fluorescent lamps.

Fig. 5 is a plan View of the tipping-off device of Fig. 4. g 7

Referring to Fig. l, the rotary turret machine illustrated thereincomprises essentially a circular platform or wheel I which is supportedby, and pivots with, a shaft 2. At spaced intervals near the peripheryof the platform I, are located a number of combined heads and chucks 3for receiving and holding elongated tubular glass envelopes such asfluorescent lamps d. Each head 3 comprises a tubular sleeve 5 which isadapted to fit over and make hermetic contact with the upper exhausttube 6 of lamp 4. In addition, head 3 comprises a number of clampingpieces or jaws 1 which grip the upper end of the lamp and hold it invertical alignment below the head. It will be understood that the turretis intermittently rotated or indexed in order to advance each headthorugh a series of work positions whereat different operations areperformed on the lamp.

The tubular sleeve 5 is connected to suitable evacuating apparatus whichis not shown in the drawing. It will be understood that the purpose ofthe machine is to permit flushing the air out of the lamps, evacuatingthem, filling them with gas, and tipping-off the exhaust tubes whilesimultaneously annealing at suitable temperatures. A lamp :begins itscourse through the machine at a position P and is inserted in a chuck 3'at that position by the operator. With this. particular machine,immediately after its insertion into the chuck at position P, the lampenters a semicylindrical annular oven 8; and during the course of itstravel through this oven, the lamp is heated to a suitable temperaturefor the processing that takes place after its emergence at position P.Also, during the course of its travel through the oven, the lamp isflushed with a suitable gas for cleaning out any air, moisture, andother impurities which may be occluded within the interior glass wallsof the envelope. Upon its emergence from oven 8 at position P, it isdesired to seal or tip-off the lower ex .aust tube of the lamp. It willbe understood that upon emergence at position P, the lamp is at atemperature of several hundred degrees centigrade and is like- 1y to beslightly bowed. Since the lamp is supported exclusively from its upperend, even a very slight bowing will cause a considerable displacement atits lower end. Moreover, the lamp is emerging from a hot oven into roomair at a relatively cold ambient atmosphere, and the unavoidable suddenchilling of one side causes a bowing in the direction of chilling.Although the total average amount of this bowing is unimportant, theactual amount varies between successive lamps; and, in practice, it hasbeen found that with an eight-foot fluorescent lamp of the type commonlyknown as the 96-T-12, a variation in 4 displacement at the lower end ofas much as one inch occurs during manufacturing.

The tipping-off apparatus must, accordingly, be designed to movevertically upwards as each succeeding lamp reaches the operating stationin question. Since the lateral position of the bottom ends of the lampsvaries, the tipping-01f apparatus must also be designed to have thenecessary freedom of motion in a plane normal to the axis of the lamp.The flexibility of the system must be such that it be capable ofsurrounding the lower exhaust tube with the requisite tippingoif flamewithout exerting any undue side thrust and without bending the lamp inits softened state. Since the lamps are very long and slender and quitepliable at the temperature at which they emerge from oven 8, it will beunderstood that the tipping-01f apparatus must be free to movetransversely in a horizontal plane with a pressure exerted thereon bythe end of the lamp not in excess of a few ounces.

The very stringent requirement outlined above are met by a constructionof a tipping-off apparatus embodying my invention and illustrated inFig. 2. Referring now to Fig. 2, there is shown the fluorescent lamp 3which is connected to a head3 of the exhausting apparatus. It will beunderstood that the upper clamping jaws l have not been shown in thisfigure and that a very substantial midportion of the lamp has beenbroken away. The lamp is shown in the position which it would occupy atthe lower tipping-off station corresponding to P in Fig. 1. The actualhead 3 connected to the lamp may correspond to that shown in theexhausting apparatus disclosed in U. S. Patent 2,247,513 to A. J.Marshaus. When the head 3 and the lamp 4 first enter this particularwork station, the tipping-01f device lies in a downwardly retractedposition below the path of movement of the lamp and out of operativerelationship therewith.

The tipping-01f device comprises a pair of gas burners l I and i2 whichare mounted on a head l3 and which have upwardly and inwardly inclinedjets for directing the flames to a common central point. A funnel-shapedguide I4 is affixed to head I3 by means of a bracket l5 and comprises anumber of outwardly flared fingers M which are adapted to engage andlocate the lower end of lamp 4. Head 13 is mounted on a post I6 attachedto a disc ll, the whole constituting the upper supporting means for theburners. The upper supporting means is provided with a limited freedomof movement in a horizontal plane by the arrangement whereby disc I!floats on a ring of ball bearings I8 located within a housing i 9. Thishousing is attached to the upper end of a rod 29 which may movevertically upwards and downwards and constitutes part of the lowersupporting means for the burner. The relatively movable upper and lowerportions of the supporting means for the device, that is, disc I: onwhich the upper parts are mounted and housing [9 which is afiixed to thelower portion, are characterized by superposed surfaces perpendicular tothe vertical direction of movement of rod 223. These superposed urfacesare constituted by the lower surface ll of disc I! and the upper planesurface E9 of housing It. The ball bearings interposed between these twosurfaces are maintained in spaced relationship about an annular area ofdisc H. A ring-shaped cover plate 21 is attached over the housing [9 andserves to keep disc l1 and the burner supported thereon in spacedrelationship with respect to the housing and prevent any tipping ofthese elements by a side thrust.

Rod is adapted to slide within a bracket 22 which extends from the framof th turret machine and serves as a means for holding the entiretipping-off device at the correct position with respect to the workstation. The vertical motion is transmitted to rod 20 and by means of alinkage comprising a spring 23 contained within the hollowed out lowerextremity of rod 20 and compressed by a piston 24. Piston 24, in turn,is driven by means of a lever 25 which is linked thereto by a pin 26fitting in a suitable slot within the lower end of the piston. Lever 25is pivoted on a shaft 25 and is normally biased by means of a spring 21which extends to a stationary part of the frame for the machine. Lever25 has a roller 28 at its opposite extremity which roller is adapted tofollow the contour of a cam 29 so as to be actuated thereby. Since theoperation of the tipping-off device must be synchronized with theindexing movements of the lamps in the turret machine to and from thespaced work stations, the cam 23 is preferably actuated by the drivingmeans for the turret machine.

The upper floating section of the tipping-01f device is provided withsufiicient freedom of movement in a horizontal plane to permitadjustment for any ordinary variation in the positioning of the lowerextremities of the lamps 4 which may be encountered during the course ofmanufacturing operations.

After a lamp has been indexed into the station corresponding to thetipping-off operation, the cycle is initiated by an upward movement ofpiston 24 which results in an upward movement of the floating portioncomprising the burners and the guide It, The upper extremities of theguide fingers M are spread out enough that no matter where the lowerextremity of the lamp happens to be positioned with respect to the workstation, it will strike the inwardly sloping surface of one of thefingers. Immediately thereupon, the upper floating portion of thetipping-off device will shift sideways by movement of the disc I!overthe upper surface 19' of the housing I9. The lateral movement willcontinue while the tippingoff device is moving upwardly until finallythe lower end of the lamp is seated squarely within the flared guide M.

The preceding operations permit the exhaust tube 3%, extending beyondthe lower end of the lamp 4, to pass through a central aperture 3| inthe lower shield portion 32 of the guide [4. Finally, at the limit ofthe vertical upward movement of the device, the shield portion 32 of theguide 14 abuts directly against the lower end of lam 4 as shown in thedrawing, and the burners II and I2 are then properly positioned todirect their flame to melt and seal the lower extremity of the exhausttube 38. The motion of the operating lever 25 and piston 24 is actuallygreater than what is normally required to assure positive seating of thelamp in guide [4, and the excess motion is absorbed by the compressionof spring 23 located between the lower end of rod 20 and the upper endof piston 22. This is in order to permit positive seating of the variouslamps in spite of dimensional tolerances and variations. In between thetimes when the tipping-off device is bearing against the lower end of alamp, the expansion of spring 23 is limited by means of a pin 34 whichis carried by piston 24 and rides in a longitudinal slot 35 in the lowerportion of rod 2B.

The melting of the glass and the sealing of the exhaust tube is broughtabout by the action of the relatively hard flames from the burners I!and I2 and consists, in this particular instance where a short exhausttube is presented, in fusing and working the end into a permanentlysealed tip. Should the exhaust tube 30 be of excessive length, theportion below the seal can be caused to separate and fall from theportion remaining attached to the lamp. In the present instance thelower exhaust tube which the tipping-ofi device described herein isdesigned to seal, is not connected t any exhausting apparatus. Itsfunction is different from that of the exhaust tube extending from theupper end of lamp 4 and connected to one of the heads 3 of the turretmachine. The lower exhaust tubes served their purpose during theflushing operation of the lamp and are of no further use duringsucceeding manufacturing operation.

Following the tipping-off or sealing-off of the exhaust tube 30, thetipping-off device is lowered away from engagement with the end of lamp4 by means of suitable movement of cam 29. This permits rotation of theturret machine. and the indexing thereof to the succeeding station whileanother lamp is brought into the work station P associated with thetipping-off of the lower exhaust tube. It will be understood that thelowering of the device is performed by the reverse movement of theoperating lever 25 and completes one cycle of operation. Succeedingcycles of operation follow the same course as that just described.

Since it is desirable that the device be kept from turning in order toprevent the flexible tubes II and I2 supplying gas to the burners II and[2, respectively, from engaging extraneous apparatus and interferingwith the operatiion of the device, means are provided for so doing.These means comprise a pin 31 extending from housing 19, which pin 31 islocated in gzvertical slot in an arm 38 attached to bracket In theembodiment of my invention illustrated in Figs. 4 and 5, certainimprovements have been incorporated which have been specificallydesigned for the manufacturing operation of tipping-01f the lowerexhaust tube in an eight-foot tubular fluorescent lamp of the typecommonly known as the 96-T-12 and 96-T-8. It might be mentioned thatthese designations signify tubular florescent lamps 96 inches in nominallength and 12/8 and 8/8 inches in diameter, that is 1 and 1 inches indiameter, respectively.

In connection with the tipping-off device of Fig. 2, it will be realizedthat, after a particular lamp has been sealed off, the device remains inWhatever position of lateral displacement it occupied when it waslowered away from the previous lamp upon which it operated. Undercertain circumstances, this may lead to difficulties. Thus, if apreceding lamp had an extreme deviation to the right whereas thesucceeding lamp has an extreme deviation to the left, the amount oftravel or lateral displacement required of the guides and burners isdoubled. With very long lamps, in connection with which the variationsin deviation of the lower ends are apt to be considerable, it becomesvery desirable to provide som means for automatically recentering thedisc 11 and the burners with respect to the housing I 9.

Referring to Fig. 4, wherein there is shown a tipping-off device ofgenerally similar construc- 7 tionto'thatof Fig. 2, the automaticrecentering feature'is provided'by'means of a lighthelicalspring-dfl'which is secured at one end by means of a pin M to the lowerextremity of a rod I and which is connected at its upper end by means ofa flexible wire '42 to a pin 43 fixed to the'movable disc Ill. Wire'42passes through a guide bushingEG located within rod [2!], so that'theportion of the wire between the bushing and pin '43 is bent outofth'ev'ertical whenever znovable disc lll moves out of its'centralposition. v The spring'AO'is adjusted to exert-at all times a slighttension on the wire 42 as a result-cf which disc I I1 is automaticallyreturned to a central position within the housing H9 whenever the deviceis lowered away out of engagement with a lamp.

In this improved embodiment of the invention, the fingers H4 of theguide H4 are provided with heating'means for raising their temperatureto a'p'oint approximately equal to that of the lower-end of the lampwhen it emerges from the oven 8. The fingers are V-shaped in crosssection and open to the rear, that isfon the side facing radiallyoutwards. The heating means comprise small jets or nozzles 44 locatedbelow the guide fingers l M and connected to a gas supply ring 45. Ring45 is supplied with gas through an inlet tube 46' which is normallyconnected to a supply'by means of flexible rubber tubing. The bottomplate or seat 32 of the guide H4 is shaped somewhat like an invertedfunnel in order to guide the flame from the burners III and H2 onto thelower tip of the exhaust tube-'30.

Since the burners and guides mounted ondisc H! in the present embodimenthave a greater range of lateral displacement, it has been founddesirable'to provide a double ring of ball bearings in order to obviateany tendency toward tipping. Accordingly, two rows of balls H8 and H8are provided in a single retaining ring. Thus, onering is at all timesfully beneath the disc H! so that it is impossible for the burnerassembly mounted thereon to tip over, and it always bears evenly on theballs. A slightly different arrangement is utilized herein for limitingthe lateral displacement of disc H? with respect to housing H9. Thisarrangement consists of a vertical pin 41 attached to a mounting plate48 secured to the disc H7, and a locating ring 59 which is formed in alateral projection of the cover plate E2! of housing H9. The pin andlocating ring combination prevents the edge of the disc H1 striking thehousing H9 and possibly damaging one or the other. Rod 29 which supportsthe housing, is received in a sleeve I22 and resiliently supportedtherein by a spring I23. The tipping-off device is raised against thelower end of the lamp through an upward displacement of sleeve I22. Theexcess movement, after engagem'ntof the lamp, is taken up by compressionof spring I23, in generally similar fashion as with spring 23 in theembodiment of Fig. 2.

While certain specific embodiments have been shown and described, itwill of course be understood that various modifications may be madewithout departing from the invention. The invention is-essentiallycharacterized by the provision of the tipping-off burners and locatingguides for receiving the lower extremity of the lamp on a disc or platewhich has lateral Or transverse freedom of movement with respect to thevertical displacement of the assembly towards the end of a lamp."Although the embodiments herein have been described with all therefinements which have been found desirable for the verydelicateoperations contemplated in the use of tiemachine, such as ball bearingmountings, these refinements need not all be observed where work ofa'grosser type is satisfactory. Likewise, in the arrangement forproviding the vertical upward movement to the assembly, the refinementsfor taking care of dimensional variations in th-e'length of the lampsare not essential and may likewise be dispensed with. The appendedclaims are,-ther'efore, intended tooover any such modifications comingwithin the true spirit and scope of the invention.

What'I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. A self-positioning tipping-off device, com-' prising a heater,support means for said heater comprising an upper section terminating atits lower end in a horizontal disc and a lower section comprising avertically reciprocable rod under said upper section and terminating atits upper end in a horizontal surface for supporting said and meansholding said disc in fixed vertical position relative to said surfacebut permitting limited floating motion of the disc laterally, and guidemeans attached to said upper'section of the support means and adapted toengage with an article to behe'ated to accurately position the heaterwith respect to said article.

2. In apparatus for processing an elongated electric lamp or similardevice having'an exhaust tube projectingfrom each end thereof, thecombination of an exhaust head mounted for intermittent'movement to aseries of work stations and adapted'to' support a lampin a suspendedvertical position by gripping it adjacent its upper end, and atipping-oil device located'at one of said-work stations in verticalalignment with the exhaust head at said station and below the lamp heldthereby, said tipping-oi? device comprising heating means for fusing thelower exhaust tube of said lamp, support means for said heating means,means for vertically reciprocating said support means to carry theheating means thereon towardand alternately away from the lower end ofthe said lamp, means mounting said heating means on said support meansfor limited horizontal floating motion, and guide means mounted on saidsupport means in fixed relationship with said heating means and adaptedtoengage the lower end of said lamp-and shift said heating meanshorizontally into aco-urate relationship to said lower exhaust tube.

3. In apparatus for processing an elongated electric lamp orsimilardevice havin a vitreous exhaust tube project-ing'from each endthereof, the combination of an exhaust head mounted for intermittentmovement to a series of Work stations and adapted to support a lamp'in asuspended vertical position by gripping it adjacent its upper end, and atipping-off device located at one of said work stations in verticalalignment with the exhaust head at said station and below the lamp heldthereby, said tipping-01f 'device comprising heating means for fusingthe lower exhaust tube of said lamp, support means for said heatingmeans, means for vertically reciprocating said support means to carry'the heating means thereon toward and alternately away from the lower endof the said lamp, means mounting said heating means on said supportmeans for limited horizontal floating motion, and funnellike guide meansmounted on said support means in fixed relationship with said heatingmeans and adapted to engage the lower end of said lamp and shift saidheating means horizontally into accurate relationship to said lowerexhaust tube.

4. A self-positioning tipping-off device for fusing and sealing the endsof vitreous tubes projecting downwardly from elongated envelopesperiodically presented at a work station, with individual variations inthe positioning of succeeding envelopes, comprising lower supportingmeans defining a horizontal surface and adapted to move verticallyupwards towards the lower end of said envelope, upper support meansslidably mounted on said lower support means and adapted to move freelyon said surface in a direction transverse to said vertical movement, aguide attached to said upper support means and adapted to engage thelower end of said envelope in order to cause said upper support means tobe displaced transversely with respect to said lower support means intoposition for engagin said lower end, and burners attached to said uppersupport means for sealing off said vitreous tube.

5. A self-positioning tipping-off device for fusing and sealing the endsof vitreous tubes projecting downwardly from glass envelopesperiodically presented at a work station with lateral variations in thepositioning of succeeding envelopes, comprising lower support meansadapted to move vertically upwards towards the lower extremity of saidenvelope, upper support means mounted with horizontal freedom ofmovement on said lower support means, each of said support meansdefining a plane surface, one super: posed upon the other, and adaptedto slide, one with respect to the other, burners attached to saidsupport means for sealing off said vitreous tube, and a guide mounted onsaid upper support means for engaging said lower extremity and forcausing said upper support means to be displaced transversely to theextent necessary for centering said burners about said exhaust tube.

6. A self-positioning tipping-off device for fusing and sealing the endsof vitreous tubes projecting downwardly from glass envelopesperiodically presented at a work station with lateral variations in thepositioning of succeeding envelopes, comprising lower support meansadapted to move vertically upwards towards the lower extremity of saidenvelope, upper support means mounted with horizontal freedom ofmovement on said lower support means, each of said support meansdefining a horizontal plane surface, one superposed upon the other, ballbearings located between said surfaces for reducing the friction ofsliding, burners attached to said upper support means for sealing offsaid vitreous tube, and a guide mounted on said upper support means forengagin said lower extremity and for causing said upper support means tobe displaced transversely to the extent necessary for centering saidburners about said exhaust tube.

'7. A self-positioning tipping-01f device for fusing and sealing theends of vitreous tubes projecting downwardly from glass envelopesperiodically presented at a work station with lateral variations in thepositioning of succeeding envelopes, comprising lower support meansadapted to move vertically upwards towards the lower extremity of saidenvelope, upper support means mounted with horizontal freedom ofmovement on said lower support means, each of said support meansdefining a horizontal plane surface, one superposed upon the other, ballbearings located between said surfaces for reducing the friction ofsliding, burners attached to said upper support means for sealing offsaid vitreous tube, and a guide comprisin flared fingers mounted on saidupper support means for engaging said lower extremity and causing a sidethrust to be exerted for shifting said upper support means horizontallyto the extent necessary for centering said burners about said exhausttube.

8. A self-positioning and automatically recentering tipping-off devicefor fusing and sealing the ends of vitreous tubes projectin downwardlyfrom glass envelopes periodically presented at a work station,succeeding ones of said envelopes having variations in their positioningwith respect to said station, comprising lower support means arrangedfor vertical movement towards the lower extremity of said envelope,upper support means slidably mounted with respect to said lower supportmeans in a manner to provide horizontal freedom of movement, a guideattached to said upper support means for engaging the lower extremity ofsaid envelope and causing said upper support means to shift transverselyduring the continued upward movement of said lower support means, saidshifting being in a direction for causing said lower extremity to seatsquarely in said guide, burners mounted on said upper support means andlocated for fusing and sealing-off said vitreous tube upon seating ofsaid envelope within said guide, and a tension spring connected betweencentral points in said upper and lower support means for automaticallyrecentering said upper support means upon disengagement of said guidefrom said lower extremity.

9. A self-positionin and automatically recentering tipping-01f devicefor fusing and sealing the ends of vitreous tubes projecting downwardlyfrom glass envelopes periodically presented at a work station withlateral variations in the positioning of succeeding envelopes,comprising lower support means adapted to move vertically upwardstowards the lower extremity of said envelope, upper support meansmounted with limited horizontal freedom of movement on said lowersupport means, each of said support means defining a horizontal planesurface, one superposed upon the others, ball bearings located betweensaid surfaces for reducing sliding friction, burners attached to saidupper support means for sealing off said exhaust tube, a guide mountedon said upper support mean for engaging said lower extremity and forcausing said upper support means to be displaced transversely in orderto center said burners about said exhaust tube, and a tension springconnected between a central point in said I upper support means and acentral point below said surfaces in said lower support means forautomatically recentering said upper support means upon disengagement ofsaid guide from said extremity.

ROBERT A. KUEBLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number

